A biosensor is a device which measures the presence or level of an analyte in a biological sample. A biosensor may include three main parts: i) Biologically reactive elements sometimes referred to as a reagent. Reagents may include biological materials (e.g., tissues, microorganisms, organelles, cell receptors, enzyme, antibodies, and take acid, etc.), a biologically derived material or biomimic, wherein the reagent may be created by biological engineering; ii) a transducer or detector element which may work in a physiochemical way (e.g., optical, piezoelectric, electrochemical, etc.) to transform the signal resulting from the interaction of the analyte being measured with the reagent into another signal that can be more easily measured and quantified; and iii) associated electronics or signal processors that are primarily responsible for the display of the results m a user-friendly way.
Diabetes mellitus is a worldwide public health problem. This metabolic disorder is caused by a deficiency in, or resistance to, insulin, and can result in hyperglycemia, a condition in which blood glucose concentrations may be higher than the normal range of 80-120 mg/dL (4.4-6.6 mM). Diabetics can take medicine such as insulin to lower their blood glucose concentration but such medicines have the hazard of sometimes lowering the blood glucose to below the normal range and risk unconsciousness, organ damage and in severe cases death. Symptoms and complications may be greatly reduced through patient management and control of blood glucose levels. Consequently, biosensors which measure concentrations of glucose in a patient are in high demand. Indeed, glucose sensing biosensors are incorporated into home blood glucose meters which are widely used by diabetics to accomplish this goal.
Conventional blood glucose meters are generally glucose biosensors that analyze a blood droplet from a patient's finger prick. Biosensors combine a biological sample (in the ease of conventional blood glucose meters, blood droplets) with a physiochemical detector component (i.e., reagent) to allow for the detection of glucose (i.e., analytes) in the blood droplet. An analyte is a substance or chemical constituent that is determined in an analytical procedure. For example, glucose is the analyte in the process used in the blood glucose biosensors. Biosensors can he used for detecting or determining characteristics of any kind of analyte that can be analyzed by biological means. In a glucose biosensor used for home blood glucose monitoring, blood is applied to a test element, such as a disposable test strip, to react with an enzyme (i.e., reagent such as glucose oxidase, GOx) already deposited on the strip. The conventional blood glucose meter may detect a current, which is generally proportional to the glucose concentration in the blood droplet, allowing a calculated reading to be displayed to the patient.
Conventional blood glucose meters often require patients to prick their fingers to obtain a blood droplet. Such procedures may result in pain and discomfort for the patient, as well as an open wound vulnerable to infection, and tissue scarring that ultimately renders a site useless for sampling. In addition, the resulting blood droplet sample may be exposed to external elements which may contaminate the blood droplet sample. Accordingly, sampling and analyzing devices which may generate a biological sample from the patient for glucose testing that does not result in patient harm, preserves the integrity of the biological sample, and produces accurate biosensor results are desired.